Means for generating music electrically



Jan. 12, 1943.

A. T. CAHILL.

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A. T. CAHILL Filed Dec. 5, 1938 MEANS FOR GENERATING MUSIC ELECTRICALLY 10 Sheets-Sheet 10 LU M Patented Jan. 12, 1943 MEAN S FOR GENERATING MUSIC ELECTRICALLY Arthur '1'. Cabill, Weehawken, N. J.

Application December 5, 1938, Serial No. 244,114

40 Claims.

The object of my invention is to create an electrical musical instrument with new means for voicing and combining tones, and which gives the performer powers of expression which are far greater than those possessed by any other musical instrument known to me.

In order that the principle of the invention may be clearly understood, I have in the accompanying drawings, set forth the preferred embodiment and certain modifications of means pertaining thereto and by which the said art or method of my invention may be practiced.

Fig. 1 is a side elevation, partly in section, illustrating one form of the mechanism of my invention;

Fig. 2 is a side elevation of a modified form of a movable circuit employed therein for introducing and dropping the tone more gradually;.

Fig. 3 is a front elevation, but mostly in vertical section, illustrating the mechanism shown in Fig. l;

Fig. 4 is a view on the line 4-4, of Figs. 1 an 3, looking from below upward, of part of the current transferring mechanism;

Fig. 5 is a top view of a ribbon valve, made of very light spring material and used instead of a ball valve;

Fig. 6 is a view of the mercury make and break resistance expression device;

Fig. 7 is a top view of a few of the lowest and highest keys of the keyboard, the rest of the keys having been omitted; said figure also showing the capstan screws which operate the piano action as well as the contact wires for making and breaking the circuits, one wire being for the musical circuit, and the other for pedal control;

Fig. 8 is a top view of the movable keyboard frame;

Fig. 9 is a front view of Fig. 8;

Fig. 10 is a side elevation of the movable keyboard frame, keyboard, and supporting rails;

Fig. 11 is a top view of the rotary make and break expression device;

Fig. 11A is a partial side view of Fig. 11;

Fig. 113 is a top detail of the rotary drum contactor of Fig. 11;

Fig. 12 is a side elevation (on a smaller scale than Fig. 1) of the frame which carries the momentum pieces;

Fig. 13 is a side elevation of an electrically excited magnetic pick-up;

Fig. 14 is a side elevation of means for varying the harmonic content of the tone while it is sound- 8;

Fig. 15 illustrates means for practicing a methcd of inductive transfer of electricity by moving one coil mounted on a soft iron or steel rod, near to, partly in, or altogether into another, with means for shielding or shunting the action of the coils from their neighbors;

Fig. 16 illustrates means for practicing a method of inductive transfer of electrical energy by joining two coils more or less, as desired, by moving a bar of soft iron or steel through one coil, partly in, or altogether into, the other, with means for shielding or shunting the action of the coils from their neighbors;

Fig. 17 illustrates a means for practicing a method of picking up electrically the vibrations of metal bodies, such as strings, reeds, pipes, etc., voicing them to a uniform scale of loudness or power, amplifying them and turning them into sound;

Fig. 18 illustrates a means for practicing a method of picking up electrically the vibrations of physical bodies, such as reeds, sound boards, pipes, etc., by attaching armatures thereto, voicing them to a uniform scale of loudness, passing them through circuit controlling devices controlled by the keys or a swell, amplifying them, and then turning them into sound;

Fig. 19 is a side elevation, partly in section, of a dash pot, on a larger scale, with means for closing some of the holes or ports, at the will of the performer, so as to produce a slower drop, and therefore a better singing and more powerful tone;

Fig. 20 is a top view of a special type of key board for one hand, for varying the quality' of the tone while it is sounding, wherein each key operates a circuit controlling device for one harmonic, with means however, for attaching several harmonics, when desired, to the most easily operated keys;

Fig. 21 is a side elevation, partly in section of Fig. 20, showing the electrical connections, and a very simple and inexpensive movable circuitcontrolling mechanism which follows the motions of the key perfectly;

Fig. 22 is a top view of a special type of key board, for two hands, for more perfect harmonic control, than that shown in Fig. 20, each key operating a circuit controlling device for governing the power of one or more harmonics;

Fig. 23 is a side elevation partly in section, of a simpler and less expensive circuit-controlling mechanism, in which the dash pots and their coacting parts have been omitted, and spring-return retarding devices-substituted therefor;

Fig. 24 is a side elevation, mostly in section,

representing dash pots working in oil or other fiuid, contained in a trough, and also showing a slide which may be moved so as to cover the ports to any extent desired.

Figs. 25, 26, 27, 28 and 30 are schematic views or wiring diagrams of different methods which I use for controlling my electrical music circuits and translating them into sound;

Fig. 29 is a detail view partly in section of one of my multiple-plate variable condensers, which I use for transferring electrical energy which increases in a. logarithmic manner to the direct linear motion of the plate and also for combining the harmonics into a complex tone, and also for voicing the power of each individual harmonic, or for combining tones into chords;

Fig. 29A is a perspective detail view of one of my specially shaped stator plates, with the movable plate, l2, partly inserted therein; and

,Figs. 31, 32 and 33 are schematic views or wirlllg diagrams constituting modifications or variations of what is shown in Figs. 26, 27 and 28 respectively, but for the same purpose.

Objects of the invention My invention relates to that type of musical instrument first invented by my brother, the late Dr. Thaddeus Cahill, in which the vibrations are first created electrically by alternating current generators, or any other alternating current generating means; in which the vibrations from one source or note, are used as the ground tone, or first harmonic, for the note, or key, corresponding to that frequency of vibration, and, also, as the higher harmonics for notes lower down in the scale which are derived from this source, and by cross connections are fed down to the proper keys, one, two, three, four, and five octaves below. The individual harmonics are, in the practice of my invention, under the perfect control of the performer, and may be introduced or not as desired, and to any extent desired, from nothing to a maximum, so that tone color, or quality, is under perfect control at all times. It is possible, in the practice of my tically any musical tone quality desired. The power of every note of each individual set of harmonics is voiced to a perfectly uniform loudness, or power, by inserting in the circuit of such note the proper voicing coil to dam the current back to just the 'right amount, or by using the exact size of condenser plate to transfer the amount of power desired. The voicing coil, and particularly the condenser plate, also serves the double purpose of preventing destructive cross leaks between the various generators. The circuits of the instrument, mechanism, or system, herein disclosed, are controlled by the keys of the keyboard, and the many sets of electrical vibrations, whether from one or many keyboards, are combined and recombined, and the resulting very complex electrical waves, which may represent a whole orchestra, are then fed to a loud speaker, or speakers, on the premises, or to cables. 1

One of the objects of my present invention relates more particularly to providing an exceedingly delicate, and very perfect, touch control for governing the expression or loudness of the tones. The mechanism, constituting the herein disclosed embodiment of my invention, particularly Figs.

. 29 and 29A, is very light and simple, and is such that the power of each tone varies with every movement of the key, and remains always in exact relation to the position of the key; thus, if

invention, to create pracof the tone.

the key is depressed one quarter, the efiect on the ear will be one quarter of the maximum power; if the key is depressed one half. the effect of the tone on the ear, will be one half of the maximum power, and so on.

Another object of my invention is the complete elimination of diaphragm crack, or so called keythump. When the currents are properly handled, the tones can be taken and dropped with absolute smoothness and beauty.

Another object of my invention is to produce, in an electrical musical instrument, the perfectly responsive sympathetic attack of the piano. This I do by using a piano action, the hammers of which hit the movable circuits, such as the plates of variable condensers Whose shapes are similar to those illustrated in Figs. 29 and 29A, and s0 impart more or less motion to them according to the touch upon the keys.

Another object of my invention is to control. in such an instrument, the drip or dying away of the tones to any extent desired. I accomplish this by connecting the movable circuits to dashpots, the ports of which may be covered by movable slides to any extent desired, and so can accelerate or slow down the return movement of the movable circuits, such as the plates of a variable condenser, within very wide limits.

Another object of my invention is to reverse exactly the piano attack, or the commencement I accomplish this by having the piano hammers strike momentum pieces which will absorb the power of the hammer blow. These momentum pieces, being much heavier than the hammer, will not thro-w'the movable circuits up so far at the commencement of the tone, but in the end will shove them up just as far. This produces the efiect of the tones commencing very softly, and then gradually swelling up to the maximum loudness represented by the blow of the hammer.

Another object of my invention is the disconnectin of the piano action and the dash pots, and the positive connecting of the movable circuits directly to the keys, so that the two move together, thus making it possible to produce a great variety of expression, such as the bowed instruments, Woodwinds, brasses, etc., and the employment of the following.

Another object of my invention is the production of an electrical una corda or soft pedal, which I attain by passing the current, before it goes to the loud speaker, through a variable circuit, or a resistance, etc., or other current controlling device.

Other objects of my invention are the produc tion of the electrical loud pedal, the electrical sustaining pedal, and the voicing means, whether in instruments where the tones are generated electrically, or otherwise.

Another object of my invention is the use-of sharply pointed and properly shaped condenser plates and also amplification and necessary shielding in connection with the above powers or elements; and means for translating the electric musical waves into sound, such for instance, as loud speakers, etc.

Other objects of my invention are the joining of any, or all, of the inventions described in this specification, to the necessary shielding and amplification.

Other objects of my invention will be disclosed.

later on in this application.

Expression is the soul of music. No matter how good the tones may be, the effect is lifeless accept-1 if there is no expression. In other words, the control, at every instant, of the expression, the accent, the-power, the dynamics, of every tone, and even, when desired, of every harmonic element of every tone, is of the very greatest importance to fine music. Tones of comparatively poor quality, but with such expression, will produce beautiful music, whereas beautiful tones without expression, or with but poor expression, will not.

The principal object of my invention, therefore, is to make an electrical musical instrument by which to practice the method of my invention, and which shall have greatly improved powers of expression; which shall have, in fact, powers of expression about as great as the human hand and brain are capable of; an instrument which shall combine in its one self, the powers of expression and tone color of practically every other musical instrument. Ihave succeeded in doing this in a very simple and relatively inexpensive manner, as will be hereinafter fully explained by reference to the said drawings.

Since the epoch-making invention of electrical.

music by my late brother, Dr. Thaddeus Cahill,

waves, its derivation of harmonics, its accurate voicing of the tones, and its synthesis, or combining and blending, of any desired number of harmonics, (each of which may be of any desired power from nothing to a maximum) into any desired qualities, it is possible through electrical generation and control to have tones of any desired color or quality, of any desired power, and also to have expression of any desired kind.

My present invention relates to such an electrical musical instrument which has practically limitless powers of expression and of tone color. On such an instrument it is possible to produce musical effects never heard before from any one instrument, since a performer may build up tones of any desired quality and power, and play them with any desired expression.

For instance; I

(1) He may build up tones of fine piano quality, and play them with perfect piano expression, and with the characteristic logarithmic drop of the piano; (2) or he may play them with perfect piano expression and with a much slower drop than that of the piano, thus giving the effect of a much more powerful instrument; (3) or he may play them with perfect piano expression, that is, with the perfect dynamics of the piano when the tones are taken, but without the characteristic drop of the piano; that is, they maybe sustained like the tones of the organ; (4) or he may play these rich piano tones. and chords with the attack, and all the characteristic shadings of the expression, the crescendos, diminuendos and vibratos of the violin and bowed instruments; (5). or he may play thesepiano tones with an attack which is the reverse of 'Jhe piano, that is, with the tones coming invery softly at first, but with all the delicate shadings in power of the piano, and then growing to a maximum corresponding to the touch of the fingers upon the key, and they may then drop like piano tones; (6) or in playing these piano tones with an attack which is the reverse of the piano, the tones may be caused to drop very much more slowly than piano tones do, thus giving the effect of a much more powerful instrument; (7) or in playing these piano tones with an attack whichis the reverse of the piano, the tones may be sustained like organ tones (8) or he may play these piano tones with the characteristic attack, sostenuto and drop of the organ; (9) or he may build up tones of fine organ quality and play them with perfect piano expression and with the characteristic logarithmic drop of the piano; (10) or he may build up tones of fine organ quality and play them with perfect piano expression and with a much slower drop than that of the piano; (11) or he may build up tones of fine organ quality and play them with perfect piano expression; that is, with the perfection of the dynamics of the piano when the tones are taken, but without the characteristic drop of the piano, the tones being sustained like the tones of an organ; (12) or he may play these organ tones with an attack which is the reverse of the piano and they may then drop like piano tones; (13) or he may play these organ tones with an attack which is the reverse of the piano. and they may then drop as piano tones do, or very much slower than piano tones do, thus giving the effect of a much more powerful instrument;

(14) or he may play these organ tones with an attack which is the reverse of the piano, and they may then be sustained like organ tones; (15) or he may play these organ tones with the characteristic attack, sostenuto and termination of organ tones; (16) or he may play these fine organ tones and chords with the attack, and all of the characteristic shadings of expression, the crescendos, diminuendos, and vibratos of the violin and bowed instruments; (17) or he may build up beautiful violin tones or the tones of any of the bowed instruments, and play them with all the characteristic forms of expression set out more at length in clauses l to 7 inclusive, preceding; (18) or he may play the beautiful tones of the bowed instruments with all the characteristic crescendos. diminuendos, and vibratos of the bowed instruments, and indeed, the musician playing on my electrical musical instrument hereinafter described can do many things of great musical merit which cannot be accomplished with the bow; (19) or he may build up the soft tones of the woodwinds and play them with all the characteristic forms of expression listed more fully in clauses l to 8, inclusive, preceding; (20) or he may by proper manipulation of the expression devices, produce a very close approach to the characteristic attack and drop of the Woodwinds; (21) or he may build the characteristic tones of the brass instruments and, if desired, play them with any or all of the forms of expression listed in clauses i to 8 inclusive, as well as with their own characteristic expressions, and by a proper control of the seventh harmonic series-introducing it more or less as desired-the musician may produce most beautiful brass effects of the utmost power and without anyof the raucous effect or harshness of overblown brass; or by introducing more of the seventh harmonic series, he may produce an exact brass effect with its harsh and raucous effects when overblown; or, by introducing still more of the seventh harmonic series, he may produce a brass tone which is more brassy and has more cutting edge than ordinary overblown brass instruments; he may have this overblown brass effect on the softest as well as on the loudest passages, and he may also, by properly reducing the seventh harmonic series, have a most beautifully soft and mellow brass tone, whose quality holds unchanged from the softest pianissimo to the loudest fortissimo, thus producing much better brass tones-and also woodwind tones-than on the original instruments, the same being true of most of the other tone qualities; (22) also, he can produce, if desired, many or most of the characteristic effects of the percussion instruments, bells, etc. My instrument is capable of introducing within the scope of my invention many other effects-which I have not listed herewith.

With two manuals, the musician may produce the effects of one or more of the bowed instruments or brasses or Woodwinds, on one manual, and on the other manual the effect of another instrument, such as the piano or the organ. Or, if'

two performers play on two or more manuals on the same instrument, each performer playing one or more manuals, it is possible for one musician to play the parts of two, three or more bowed instruments, such as the violin, viola and cello, or the parts of some of the Woodwinds or brasses, while the other musician can play a full piano or organ accompaniment, or others of the orchestral. instruments. Enormously more beautiful effects, bigger, richer and broader, can be produced by two musicians playing the same instrument at the same time, than by one alone, but where it is desired to do this, the keyboards for the two players should be staggered, or offset sidewise, with relation to each other at least two, and better, three, octaves, so that each musician will be able to play the full range of his board without interfering with the other.

In accordance with my invention, I vary the loudness of the tones in the apparatus shown in my said drawings by using movable circuits, preferably, by varying the action or reaction, either or both, between vibration-transferring and vibration-receiving circuits. By these words, I mean to describe and cover, as included within my invention, any means whatsoever by which the movement of one body near to, or partially in, or altogether into, or onto, another, or the movement of bodies with relation to each other as, for example, by rotation, etc., will transfer energy from one to the other, whether that energy be lines of force, or actual electrical current or merely voltage; whether it be done by induction, capacity effect, condenser action, or screening the action of one circuit from acting upon another, etc.; or it may be done by varying the excitation in the field of the generator; or it may be done by varying the strength of the alternating current itself by cutting in and out of the circuit, resistance or capacitance, or induction, or by combinations of one or more of these methods, or in any other suitable way.

Many ways are known of varying of voltage or of current flowing in a circuit. Some are expensive, some are cheap, some are cumbrous, some are convenient. It is unnecessary to illustrate them all, and I am therefore showing only my preferred form and a few others. They are, however, such that the resulting tones can easily be controlled with the utmost delicacy and precision. I wish full protection whatever means of transfer or control are used, as being within the scope of my invention.

All the marvelous powers of expression, to which I have referred, I easily produce by moving one conductor near to, partially in, or altogether into, and out of, inductive, or capacity, or condenser, etc., relation with another conductor, or by moving an electrical screen so as to vary the action of the transmitting circuit upon the receiving circuit, and controlling its motions accurately, and

delicately, so as to produce the desired expression or dynamic changes. Or it may be done by varythe amount ing the voltage applied to the filament of a vacuum tube, to the fields of a generator, or to the exciting coil of a magnetic pick-up. For piano expression, the movable conductor should be thrown into closer relation to the live, or inducing, or transferring conductor, as, for instance, by the blow of a piano hammer, and then allowed to drop away, the rate of drop being controlled so as to produce the characteristic drop of the piano tone which is very, very fast at first and becomes slower and slower as the tone dies away, or a slower drop may be used, so as to produce a better singing tone. This gives the effect of a much more powerful instrument.

For the sostenuto of the organ, in accordance with my invention, the key merely shoves the movable vibration-receiving conductor in close to the vibration transmitting conductor, or vice versa, and holds it there as long as the key is held down. As the key is let up, the movable conductor drops back toits normal position. This mode of operation produces the characteristic dynamic effects of the organ.

For the characteristic crescendo, diminuendo, and vibrato of the bowed instruments, the key which, in this case, as in that of the organ, is directly connected to the movable conductor, merely moves up and down. As the musicians finger presses the key downward, it shoves the movable conductor more and more into the field of the inducing, or transferring conductor, or agent, and there results an increase in power, or a crescendo. As the performer releases thekey, the front of the key moves up, the back of the key goes down and draws the movable conductor more and more out of the field of the inducing or transferring conductor or agent, and there results a decrease in power, or a diminuendo. Or if the key moves up and down slightly several times in rather rapid succession, there result increases and decreases in power corresponding to the movements of the key and, therefore, of the movable conductor, so producing a vibrato very easily, in comparison with the difficulty of producing it on the violin.

It will be noted that in the above case, as well as that of the org-an, dash pots are not used. They may be used whenever desired, or they may be put out of action, whenever it is desired to do so, as it frequently is.

I thus also completely, and absolutely, eliminate all so-called diaphragm crack or key thump, which is so objectionablein musical instruments in which the electrical circuits are made and broken directly and instantly, producing a distinct shock to the electrical circuitsomething like hitting a bar of steel with a hammerand setting up transients of high and varying fre quency, which are not musical sounds but are noises, and produce on the ear an effect similar to a tap, a blow, or a pluck, both when the tone is taken and when it is dropped-when the circuit is made and when it is brokentwo distinctly disagreeable effects on every tone that is sounded. The disagreeable effect, both when the tone is taken and when it is dropped, is many times stronger and louder than the tone itself. Since the time constant of these bangs or shocks to the ear, is the same no matter how long or short the tone may be, it is evident that the proportion of disagreeable sound to agreeable sound is much greater in fast music than in slow music. Therefore, music. which, when executed very slowly. may sound pleasing, may become actually un-- pleasant when executed rapidly.

it-Eothing of this sort can happen in an instrunient constructed in accordance with my invention, since a vast number of lines of force may be cut from zero to a maximum in an instant of time, and they will be dropped in the same perfectly gradual way from the maximum to zero. They may be out faster than any human hand. can play, without any shock, diaphragm crack or key thump whatever, thus producing tones having a gorgeously smooth and beautiful attack and drop.

I produce my results, in accordance with my invention, preferably, not by having the live circuits directly initiate the tones and breaking them while the tones are still sounding, to stop them. This might give diaphragm crack or key thump. Instead, I prefer to make the primary or transferring circuit first and while the secondary or receiving circuit is still dead, immediately after which I make the secondary circuit preferably through moving some such device as a variable capacity, a variable inductance, a variable resistance or a variable condenser, etc.. or by closing the induced circuit after the inducing circuit has been closed, or in any other convenient way of varying the action, or the reaction, of one circuit upon another. Or instead, both circuits may be made at the same time, but the vibration receiving circuit must be sufficiently .far

away or well enough shielded so that the instano taneous shock in the vibration transmitting circuit has completely died away before the vibration receiving circuit has entered the field of the vibration-transmitting circuit Or better still, neither circuit needs ever to be made in the sense of a positive make and break, if they are both properly and perfectly shielded. That is, with proper shielding, the primary or inducing circuit may be connected to the generator permanently. Or when I do not use movable circuits as expression devices, I sometimes close the primary circuit direct, not by bringing it all on at one step, which makes a harsh click or bang, but by bringing it on through many properly graduated steps. Sometimes I have used fifty steps which, if they are properly graduated, are quite satisfactory. Better results, of course, are produced by larger numbers of steps, but naturally, the cost and complexity arise also. However, the small variable capacity devices are much more ideal, as they have the smoothest make and break, can be controlled easily with the most beautiful delicacy, are simple, light, quick-acting, cheap, and in every "way admirable, and their results are very appreciably better musically than those produced by any of the other ways I have mentioned. They bring the tone on with marvelous smoothness, and reduce it from a maximum to nothing in the same perfectly smooth way.

By my invention I also effect the correction of resonances. It is a well-known fact that all vibrating bodies which are compelled to vibrate to many different pitches or frequencies of vibrations have resonances, and usually very bad resonances This is true even of high-grade concert grand pianos, where proximate keys have frequently tremendous differences of loudness or of power This is true, in general, of all musical instruments, such as pianos, organs, bowed instruments, the brasses, Woodwinds, etc.

The electrical music art, to which my invention pertains, includes the picking up electrically of the vibrations of physical bodies, from strings, reeds, pipes, sound boards, etc., and to the original resonances of the vibrating physical bodies are added the resonances of the amplifying devicestubes, transformers, etc-as well as the resonances of the electrical circuits and translating devices, or loud speakers. These resonances, in some cases, tend to cancel each other out and in other cases to add, and so accentuate each other, and thus make the scale of dynamics, or power of the several vibrations that reach the ear after amplification, greater than were the resonances of the original vibrating bodies, such as the pianos, organs or bowed instruments, brasses, woodwinds, etc., on which the performer is playing, proper shielding being necessary in these cases.

I correct all this very easily, simply, cheaply and with the utmost perfection, by means of voicing coils inserted in the circuit of each individual generator or pick-up. These voicing coils may be either resistances, or impedances, or combinations of them, or anything simple and cheap, which tends to dam back the flow of alternating current from the pick-up, more or less as desired. Since this alternating current is ordinarily exceedingly microscopic, the voicing coils can also be microscopically small and, therefore, very inexpensive.

I make a regular scale of voicing coils, which starts with almost no resistance or impedance and gradually increases by very small changes or steps up to as high a point as it is necessary to go. Each voicing coil is then numbered and can be slipped into its proper position instantly. I provide a keyboard of 88 keys (though, of course, the exact number used has. nothing to do with my invention) with one voicing coil in circuit with every key, so that when a proper loudness has been determined upon for any individual tone, all the others may be equally voiced to exactly that same degree of power. One tone having been set v as a standard, the circuit of the next tone is made through the voicing coil keyboard, and the musician, who is doing the voicing, runs up or down on that keyboard, alternating the note he is voicing with the standard note he has voiced on the instrument proper, until the two produce absolutely the same effect upon the ear, and until the readings on his delicate electrical measuring instruments show that the two tones are of absolutely the same power. A duplicate of the coil on the voicing keyboard is then slipped into the circuit of that tone on the instrument and it is voiced. In this way, I can easily and quickly obtain a scale whose dynamics or power are infinitely smoother than that of any instrument in which this is not done.

This, though seemingly a small matter, is, in fact, very important. When a pianist is playing a piece in which every note that is taken by either hand is supposed to have a delicacy of dynamic relation to each of the other notes that are taken at the same time, and one note due to resonance may be twice or three times as strong as some other note in the same chord, it is self-evident that the delicate balance, and, therefore, the tone color of the chord, is completely upset, whereas on an instrument where voicing coils, as herein disclosed, are used, nothing of this sort can possibly happen, and the performer is able to bring out the delicate shadings as he wishes, and in a way which has heretofore been absolutely and totally impossible.

Where it is desirable, as it usually is, I combine amplification with this feature of voicing, as well as with all the other features of my herein disclosed invention, such as: (a) generating electrical waves in any manner whatsoever; (b) using waves of one frequency as the fundamental for one tone, and also as harmonics for other tones, by derivation and cross connection; voicing the sets of individual tones, whether fundamental tones or harmonics, to individual scales of loudness or power, by the use of voicing means such as voicing coils or condenser plates, or equivalents, of slightly different sizes, so as to produce the scale of uniform loudness, or power, desired; (d) combining all the waves taken at the same instant of time, whether they be of a fundamental set, or of a harmonic set, whether they be tones or chords, whether they come from one manual or several manuals in multi-grid vacuum tubes; (e) combining all the waves taken at the same instant of time, whether they be of a fundamental set, or of a harmonic set, whether they be tones or chords, whether they come from one manual or several manuals in multiple plate condensers; (f) controlling the power of each individual set of harmonics, as 11, 2n, 3n, etc., for delicate tone building, by passing the currents above referred to through current controlling devices; (g) combining these various complex waves which represent the various tones of the individual harmonics, into one very complex resultant wave, as for instance by passing them through multigrid vacuum tubes, or through multiple plate condensers, or the separate primary windings of transformers; (h) employing individual circuit controlling devices controlled by the keys of the keyboard, one for each key, for governing the power of expression of the resultant complex waves, or tones (coming from either the plate of the vacuum tube, or the combining plate of a multiple plate condenser, or the secondary of the above mentioned transformer) which the depressed keys represent; (i) inserting at the will of the performer, a circuit controlling device such as a movable conductor or a resistance, etc., for foot, knee or hand control, in the key circuit above referred to, so that between the two the performer has a very refined, or micromatic control of the power of the tone of each individual key at every instant; (7') striking of these variable circuits with piano hammers, or their equivalents, actuated by a piano action, or its equivalent; (is) striking of the movable circuits by piano hammers or their equivalents, through momentum pieces or their equivalents so as to reverse the characteristic attack of the piano; (Z) connecting the movable circuits to dashpots or their equivalents, so as to control the drop of the tone as desired; (m) disconnecting the piano action and the dash pots, and the positive connecting of the movable circuits directly to the keys, so that the two move together, thus making it possible to produce a great variety of expression, such as the bowed instruments, Woodwinds, brasses, etc., and the employing of the following, viz: (n) the electrical una corda, or soft pedal, produced by passing the current, before it goes to the loud speaker through a variable circuit, or a resistance, etc., or other current controlling device; (0) the electrical loud pedal; (p) the electrical sustaining pedal; (q) voicing means, whether in instruments where the tones are generated electrically, as for instance by rheotomes, alternating current generators, vacuum tubes or oscillators, oscillating crystals, light interruptors, interrupted circuits, heat, etc., or by any other means whatsoever, or where they are picked up electrically from vibrating bodies, such as strings, reeds, pipes, sound boards, etc.; (1') amplification in connection with the above powers or elements; (s) means for translating the electric musical waves into sound, such for instance, as loud speakers, etc., with proper shielding of all necessary parts.

In his Patent No. 580,035, dated April 6, 1897, my late brother, Dr. Thaddeus Cahill, showed a form of power piano action, which worked by induction. In this action, the hammer struck a soft iron bar which carried a coil at one end, near or into a solenoid, in which the musical current was pulsating (see his Fig. and the coils V and V). Or he struck a soft iron core which slid between the stationary coils V and V', near or into the solenoid V, thus inductively joining the two coils, V and V by magnetic lines of force, which produced an induced cur rent of greater or less power in the coil V, in accordance with the position of the softv iron plunger 21 (see his Fig. 17).

This action, however, was not in reality a piano action, but an organ, with the attack of the piano on the taking of the tones which were then held and dropped like an organ. While it did have the sympathetic expression of the piano, so far as the dynamics of the tone at attack were concerned, it did not have the several other vitally important characteristics of the piano. It did not have the all-important characteristic logarithmic drop of the piano, since the brake R37, shown in his Figs. 15 and 17, held the movable coil V, or the bar 21, in whatever position it was thrown by the hammer, till the key was released. This kept the tone sounding at a dead level of power as long as the key was held down. Nor did it have any provision for loud, soft, or sustaining pedals, without which the present piano could not be played satisfactorily. Instead the tones were sustained at whatever power they were taken, as long as the keys were held down. Nor did it have any provision for shielding without which amplification (totally unknown at that time) would be impossible. Nevertheless, that was a great improvement over the organ, in that the tones could be taken with all the beautiful expression and accent, the wonderful delicacy of dynamic attack of the piano, instead of the monotonous dead level of the organ. But they would sound at that level as long as the keys were held down. And it also lacked the various other all-important characteristics of the piano, such as (a) the most striking thing about the piano, namely, the characteristic or logarithmic drop of the piano tones; (b) the una corda or soft pedal; (0) the sostenuto or sustaining pedal; and (d) the damper or loud pedal.

Nor did the said Thaddeus Cahill have the power, with his action, to play from one instrument, real piano music, organ music, the music of the bowed instruments, the brasses and Woodwinds, bells, percussion instruments, etc., as I have on my instrument, playing each with its own peculiar tone color, and with a very great degree of fidelity to its exact expression, e c.

In practicing my invention, and utilizing the powers of modern amplification, I move very small and light bodies with the utmost delicacy and precision, and transfer their motion into either voltage or electricity, by inductance, 'capacitance, or in any other manner, and then amplify that to any degree desired. By the use of dashpots, or any other suitable means of controlling the return movement of the movable circuits, I may drop the tone at any desired speed, either with the present characteristic drop of the piano tone, or drop it more slowly in the beginning, which gives my electric piano herein disclosed the effect of a much more poweriul instrument, with a better singing tone than the real piano. Or I may drop it faster than the piano, thus producing a very staccato result. I can also easily and quickly disconnect the piano action and the dash pots, and connect the keys directly to the movable circuits, and so produce the effect of almost any instrument.

In my electrical musical instrument, herein disclosed, I have pedals which are easily the equal in every respect, and the superior, in some respects, of the best pedals on grand pianos, and are far superior to the pedals on upright pianos. My soft pedal cuts down the volume of sound, merely by controlling the power of the electrical current that is being translated into sound, in any convenient way, such as by passing the current througha resistance, an inductive capacity, an inductive resistance, a variable condenser, etc., or by changing the taps on the transformer, and therefore the number of coils used, or by varying the voltage applied to the filament of a vacuum tube, or in any other convenient way; or it may be done by varying the fields of the generators, of the pick-ups, or of the speakers, etc. I may provide a graduated soft pedal, such as a variable condenser which controls the power, not merely by one step alone, as is the case on pianos, but by any number of steps, to any degree desired, merely by putting the pedal down farther and farther.

In the instrument herein disclosed, as the pedal goes down, it compresses a spring which ofifers an ever-increasing resistance to its depression, so that it will not work too easily. It also, as it goes down, cuts in more and more resistance, or cuts out more and more capacity, or changes the taps, and so varies the number of active turns used on a transformer, or moves the plates of a variable condenser, or changes the voltage on the filament of a vacuum tube, etc. Any of these actions will weaken or soften the tone more and more as the pedal is pressed down farther and farther. If a performer wishes to cut the tone down very much, all he has to do is to press harder on the soft pedal.

As herein fully disclosed, my pedal gives the performer added powers,'since by combining it with the touch of his fingers on the keys, he has a micromatic' adjustment of the volume of the tones. It requires a great deal of skill for the performer to play very soft or pianissimo passages at great speed on the piano, since the slightest inequality in touch will either leave the tone out altogether or bring it in too strongly. On my instrument hereindisclosed, however, he can almost entirely suppress the tone by the soft pedal and put his keys down almost or quite to the bottom each time, either very softly or with very great power, and still get the pianissimo effects which he desires. He can, therefore, produce the desired results with far less technique on my instrument than on the piano itself. When the soft pedal is depressed on an upright piano, it either (a) inserts a piece of felt between the hammers and the strings; or (2)) holds the hammers closer to the strings. The former deadens the blow of the hammers on the strings, and the latter shortens the travel of the hammers, and so reduces the power of the blows and therefore of the resultant tones. In neither case is the quality of the tone changed to any great extent.

But softening the tone is only a part of the effect skilled musicians wish to produce by the soft pedal when playing on the grand piano. When the una corda, or soft pedal, is used on a good grand piano, a totally different quality of tone is produced, because the pedal moves the whole action sideways slightly, so that the hammers strike one fewer string than they normally do. The string, or strings, which are struck, have the characteristic sharp attack and piano tone, while the other string, which was not struck by the hammer, but is only actuated sympathetically by the vibrations of the sound board, and air, produced by its brother unison strings, swings more slowly into sympathetic vibration with the unison strings, but with a very different tonal attack and tone quality and expression, the combination thus making a very beautiful effect. I produce this result, preferably, by the sustaining pedal moving a rod which controls the proper group of harmonics, in the proper proportions, to produce the tone desired, or the combination of harmonics may be brbught in by a tablet on the keyboard.

The effect of the sostenuto, or so-called Steinway pedal, is, by my invention, easily obtained to perfection, by the pedals merely moving the contact screw-carrying bar or bars, 22a, 22a, down, so that all the contact screws will make contact with the wires below them, when the keys are in their normal position. When a note is sounded under these conditions, and the key returns to its'normal position, the rear end of the key no longer hits the current carrying wire, or wires, 21, 2|, so breaking the musical circuit because the pedal has shoved these wires downward out of reach of the key. The tone will, therefore, keep on sounding until the pedal is released, and the contact screws rise, and so break contact with the current carrying wires, 2|, 2|.

Referring first to Figs. 8, 9, and 10, the supporting rails for the movable keyboard frame are indicated at the movable keyboard frame at i 2, and the movable frame-holding clips at 2a, 2a.

0n the frame 2 are provided extensions 2b, 2b, for moving the frame and the keyboard backward and forward. Key alignment pins are shown at 20, 2c, and the key pivot pins at 2d, 2d. The white keys of the keyboard are indicated at 3, 3, the black keys at 3a, 3a, and the capstanscrews at 3b, 3b. the piano action.

In Fig. 1 the felt return stop for the keys is represented at 4. I have indicated the push pieces for producing the varied musical expressions at 1, I, and the guide for the said push pieces at Ia. Levers actuated by the push pieces I, 1, are shown at 8, 8, having pivots la, 8a. The connecting pivots from the push rods 1, I, to the levers 8, 8, are represented at to, 8b, and pivot supports for the levers l, 8, at 80, 8c, attached to a rail 8d.

I have represented connecting links at 9, 9, extending from the levers I, 8, to the fly levers I0, "I, connecting pivots between the levers O, I, and 9, 9, being shown at 9a, 9a, and pivots connecting the levers 9, 9, and II, I at 9b, 9b. The links 9,9, rest upon a stop 90, a piece of felt, 9d, being provided on the stop 90, to suppress noise and vibration. Fly levers l0, l0, pivoted at Ilia, Illa, are struck by the piano hammers 26a, 26a, hereinafter referred to, and in turn impart motion to the movable plate, or plates, l2, l2, shown in Fig. 1 and also in Figs. 3, 4, 21, 23, 29 and 29A, and a modified form whereof is shown at no,

These capstan screws work no, Fig. 2, for introducing and dropping the tone more gradually. The fly levers l0, ID, are provided with felt pieces |b, IUb, and adjustable returning springs for the fly levers l0, H), are provided at lllc, I00. The said levers III, In, are supported by pivot brackets llld, llld. I provide suitable tension adjusting levers I having pivots Ila, No, for the springs'lilc, Mic, with pivot supporting brackets lib, llb, for the levers II. I have indicated adjusting screws at Hal, Hd, on a threaded bar He, and lock nuts at He, He.

The movable current-receiving plates are represented at |2, |2, in Figs. 1, 3, 4, 21 and 23, and a modified form thereof is represented at l2b, l2b, Fig. 2, with insulated guides I20, I20, Which introduces and drops the tone more gradually because of the peculiar form thereof. Other modified forms are shown at Ma to Hg, in Figs. 29 and 29A. The plates i2, i2, are fast in plate holders l2a, |2a, and the upper ends of the wires IId, I'Id, are fast in the plate holders |2a, i2a, while the lower ends of the wires |'|d, lld, are fast in the plungers Ha, Ha, of the dashpots I1. The extending ends of the plate holders |2a, l2a, will strike against the felted stops |2d, |2d, when the plate is at the top of its stroke.

Referring again to the form shown in Fig. 1, insulated wheels, serving as guides for the plates l2, l2, are shown at l3, l3, having pivots I3a, |3a. With the said plates l2, l2, co-act the stationary current-transferring plates I, I4, shields being provided as best shown in Figs. 1, 3, 4 and 29 at l5, l5, and also in Fig. at 35e, 35f, 35g and 3571., and in Fig. 16 at 36e, 36}, 369 and 36h. Desirably the plates I4, H, are attached to insulated blocks |6, |6.

I shall next refer to the feature of my invention which, for briefness of reference, I shall in subsequent parts of the specification refer to as dash pots, but which differ widely in construction and function from any dash pots of the prior art. Referring broadly thereto. each such dash pot as herein disclosed may be said to consist of a cylinder open at the top and in which a plunger moves up and down, said cylinder having one self-closing inlet valve in or near the bottom and a row of exhaust ports down at the side or sides, which said plunger closes successively in its descent. The dash pot may also be defined as a chamber open at one end, in which a plunger slides in and out, said chamber having a selfclosing inlet port at or near one end and a series of exhaust ports along the sides which the plunger covers successively as it moves into the chamber, the plunger automaticallycontrolling its own speed of return. Of course, the chamber may be of any suitable shape, whether round, square, hexagonal, etc.', but in practice round cylinders are more practical, though it would be possible to provide other shapes with pistons shaped to match.

Referring to Figs. 1 and 3, I have represented dashpots at H, H, the said dashpots having plungers Ila, Ila, and being provided with valve springs b, llb, and ball valves I10, I10. Or I provide very light spring washers He, He, Fig. 5, stamped so as to give them the utmost flexibility and used in place of the ball valves. To

the bumpers Ha, Ha, hereinbefore referred to are connected wires l'ld, lld, the other ends being attached to the 'plungers Ila, l'la. These wires carry lock nuts Ht, Wt, so that the springs I00, I00, will insure the return of the plates l2, l2.

The valve release levers shown at IS, IS, are 7:!

pivoted at I911. They have wire extensions I917, I911, bent upwards at the ends for raising the balls I10, Ho. The valve-release actuating arms are shown at 20, 20, being pivoted at 20a, 20a, upon brackets 20!), 20b. The said arms 20, 20, are connected by rods 20c, 200, which are moved by the wires 20d, 20d, set in the keys 3, 3. When the keyboard is moved backward, as shown in Fig. 1, the wires 20d, 20d, shove the rods 20c, 20c, backward. This action moves the arms 20, 20, backward and the rollers 20c, 20e, depress the rear ends of the levers l9, l9. This raises the wires lab, I91), and they raise the balls and so.

open the valves. Contact springs are represented at 2|, 2|, having contacts 2|a, 2|a, and insulated bars 2|b, 2|b, are provided to hold the springs 2|, 2|, in position. An adjustable contact frame is represented at 22. It carries insulated current-carrying bars, 22a, 22a, into which contact point carrying-screws 22b, 22b, have been screwed. These screws are held in place by lock nuts 22c, 220. The rail to which the frame-carrying supports 222, He, for the rod 22 are screwed, is shown at 22d, and the rod on which the frame 22 is mounted, is shown at 22 Screwed fast to the rail 22d, is a stop 22g, for the frame 22. A spring which holds the frame 22,

, in its normal position, is shown at-.22h, and a pushrod for bringing the contact screws 22b, 221), into contact with contact springs 2|a, 2|a, is shown at 221'.

Momentum pieces 23, 23, shown in Figs. 1, l2, and 23, are represented as pivoted at 2341.. The said momentum pieces, 23, 23, are carried by the frame 24, pivoted on a stud shaft 240,. I provide the stop 24b, for the momentum pieces 23, 23, it

being riveted to the frame 24, which also has a returning spring 24d, for returning the said frame to its normal position, and at 24c, a stop is provided for the frame 24. Also, at 24), a

. stop is provided to limit the backward motion of the momentum pieces 23, 23.

I have represented a pull rod at 240, for moving the frame 24, and at 25, 25, the part of the piano action which is actuated by the capstan screws, 3b, 3b. Felt pieces 25a, 25a, are glued to the parts 25, 25, of the piano action. The shanks of the piano action hammers are indicated at 26, 26, and piano hammers that strike the levers |0, |0, are shown at 260., 26a;

I have represented a separately excited electrical pick-up at 30, in Fig. 13, and, at 30a, the exciting or field coil, while the telephone coil, or pick-up, is indicated at 30b. In Fig. 14 I have represented a rocking tablet at 32, attached to a casting 32a, mounted upon a rod 32b, the downwardly extending arm of which carries a pin 32c, sliding in a slot in the upwardly extending arm of the casting 32d, the laterally extending arms of which are covered with a conducting material 32e, such as silver. A comb of insulating material 32g, guides the multiple circuit-closing wires 32h, 3271., as they rise and fall when they are moved by the arms 32d, 32d, and so make or break contact with the conducting strips 32c, 32c. It also keeps them separated from each other.

In Fig. 15, a hollow solenoid is represented at 35, into whose central hole a smaller solenoid, 35a, carried on a soft iron, or steel bar, 35b, which slides loosely in bushings 35c, 350, set in non-magnetic plates 35d, 35d, may enter more or less. Metallic shields, or shunts, for catching stray lines of force, and so preventing one set of coils from acting on any of the others, are

shown at Ne, 35}, 350 and 35h. The shields lie and 35!, are of magnetic material, while the shields 35g and 3571, are of non-magnetic ma terial.

In Fig. 16 a hollow solenoid is represented at 36, and another at 38c. A bar 36b slides lightly in guides 35c, 35c, and consists of an upper and lower portion of soft iron or steel, 36c, and lid, respectively. It is joined by a piece of brass, or other non-magnetic material, 36c, used for insulating, or shielding, purposes. When this bar slides into, or out of, the coil 35, it joins the two coils inductively. Soft iron or steel shields are shown at 36! and 369, while a. copper washer is shown at 36h, the whole shielding, or shunting, being so designed that it will prevent stray lines of force from reaching any of the other transferring devices.

At 38, in Fig. 1'7, I have represented an electrical pick-up, and at 380, a string. A voicing coil is represented at 38b, an amplifier at 38c, and a loud Speaker at 38d.

In Fig. 18, I have represented at 38, an electrical pick-up and an armature at 39. A voicing coil is represented at 38b, a. circuit controlling device at 39a, an amplifier at 38c, and a -loud speaker at 38d.

In Figs. 17 and 18, like parts have the same reference character applied thereto.

In Fig. 19, the dashpot (on an enlarged scale) is represented at H, the plunger at IIa, the ball return spring at I'Ib, the ball at I10, and the connecting wire at IId. Studs, III, III, are set in the plate I'Ig, which studs carry spring-compressor units IIh, IIh, whose soft heads I11, Hi, can be pressed against the port IIk, IIk, and so close some of them, thus holding the tone for a greater period of time. It will be observed that by moving the plate IIg inward, alternate ports are closed, thus prolonging the tones.

A little key board is illustrated in Fig. 20, in which the special white finger keys are shown at 40, 40, the black finger keys at 400, 40a, specially shaped white thumb keys at 40b, 40b, and corresponding black thumb keys at 40c, 40c. Contact wires are indicated at 48d, 40d, and insulated current-carrying bars at 40c, 4ile, into which contact screws 40!, 40!, are threaded. An insulated bar 409, carries the rear ends of the current-carrying springs, 40d, 40d.

In Fig. 21, the dashpots and their related mechanisms have been omitted, and the wires I 1d, IId, simply slide up and down in guides IIm, IIm.

The special white keys for the two-hand harmonic control key board shown in Fig. 22, are represented at 4| and the black keys, at Ma.

In Fig. 23 I have represented, as a substitute for the dashpots, a spring-retarding device for slowing down the return motion of the plates Individual springs 42, 42, are pressed against the wires IId, Hit. The springs 42, 42, are carried in a common holder 420, which is pivoted on the rod, 4217, set in the support and stop bar, 420. The holder, 42a, is normally held against the stop'bar 420, by a strong contractile spring 42d, but may be withdrawn by a Pull on the rod 42h. The movable holder, 420, carries an upwardly extending plate 42a, in which are set a row of screws 42 42!, one for each key. These screws can be adjusted so as to put a dellcate pressure on each of the wires IId, Ild, through the springs, 42, 42, and the screws can then be locked in place by lock nuts 42a, 42a. The wires I'Id, I'ld, slide in guides IIm, Wm.

If the parts are manufactured with precision.

the pressure of the springs 42, 42, against the wires IId, IId, will create a friction between the springs and the wires, and also between the wires and the guides, I'Im, I'Im, through which the wires slide, which will tend to retard the return movement of the plates, i2, I2.

Fig. 24 represents dashpots working in a liquid such as oil contained in a trough. Up, The size of dash pots that can be used musical instruments is strictly limited, and, since air is an exceedingly thin and light medium, the ports in the dash pots must be very small, with the consequent possibility of their becoming clogged by particles of dust, or oil. By using a fluid such as oil, however, it is possible to use smaller dashpots, and very much larger ports, with a consequent very great reduction in chances of trouble. Said Fig. 24also shows a slide Us with corresponding ports, on the side of the dashpot, by moving which the performer may cover the ports, more or less to any extent desired, and so control the drop of the tone through a very wide range of timing. Of course, all the ports can be made very much larger than where air is used.

Fig. 1, which is a view, partly in section and partly in elevation, on the line I, I, of Fig. 7, shows the keys, the dashpots, one form of my variable condensers, the hammers which actuate the same, the air valve-releasing mechanism, the means for connecting or disconnecting the keys either to or from (a) the piano action; or (b) operatively to the plates I2, l2, with their appurtenant parts. Therein is shown, as stated, one form of my momentum pieces, 23, 23, and th frame 24, for carrying the same and introducing them between the hammers 26a, 25a, and levers III, III, so that the hammers will strike the momentum pieces directly, and thus reverse the action of the piano, since the said momentum pieces, being of considerable mass with relation to the weight of the hammers, will absorb the blow of the hammers, changing it into slower motion, which will gradually shove the levers III, III, upwards until they eventually reach approximately the same place they would have reached if struckdirectly. They will, however, reach this position through a slow and gradual movement, instead of through an almost instantaneous movement, which would result if the hammers 26a, 26a, struck the levers II, I0, directly.

Referring further to the form of my variable condenser or capacity, shown in Fig. 1, it is to be noted that this may consist of two, or more. plates of suitable conducting, or magnetic, metal, I4, l4, to which the generator is connected; or the plates I4a, I41), I40, Hit, Me, I4 and M9, to which the generators are connected. The movable plate or plates, I2, I2, also shown in Fig. 3, slide lightly, in guides I3, I3, in between the stator plates I4, I4, and in close proximity to them as shown. Said plates I2, I2, feed current to the separate grids of the combining vacuum tubes as shown in Figs. 25 and 27. Or as shown in Figs. 26 and 30, they feed separate primaries on combining transformers, and in Fig. 28, they feed the separate plates of combining condensers, and owing to the powers of modern amplification, and the small amount of current required to feed the speaker or speakers, it can be very small and light. Said plate I2b, may have nonmagnetic guides at either end, as shown in Fig. 2, or .slide between insulated groved wheels I3, I3, as shown in Fig. 1. The upper or near ends of the guides I2c, I2c, of Fig. 2, are always entered between the plates [4, 14, so that the plate, l2b, is always ready to slide easily, lightly, and rapidly in between the two plates,v [4, I4, whethershoved in by a push or thrown in by a blow. Since the plates I2, l2, normally stand outside the field of the plates l4, M, which are in the shielding metal box or trough l5 made of shielding material having suitable openings in the bottom through which the plates l2, l2 enter, so that no current will be induced in theplates l2, l2, even though full current is pulsating through the plates, I, I4. But as the plate 12 begins to enter the field of the plates l4, l4, it will first cut one line of force and will gradually cut more and more until it is entirely inside the plates l4, l4, when it will have reached its maximum. As it drops backward out from between the plates l4, H, the action is reversed, and the tone dies away with the utmost beauty and velvety smoothness. This may be a slow action or process, or a very fast one. If hit a sharp blow by something, such, for instance, as a piano hammer, it may be thrown up in a very small fraction of a second, and so produce a beautiful percussive effect.

In fact, the tone may be brought on more suddenly, and much more beautifully, than is now accomplished on the piano, since it takes'an appreciable time for the blow of the hammer to set the string and sound-board into motion, whereas my movable conductor can be struck up in less time, thus producing the percussive effect and accent of the piano, but entirely without the objectionable crack of the hammer.-

By attaching it to a dashpot IT, as described, or to any other convenient device, which allows very free and rapid movement on the upstroke, and also at the commencement of the down, or return movement (out from between the plates l4, I4) with a pre-determined, constant, and rapid, slowing down thereafter, the characteristic logarithmic drop of the piano tone may be produced.

Of, if the musician desires to play with the characteristic sostenuto of the organ, it is only necessary to shift the piano keyboard inwards a fraction of an inch, back or away from the performer. This will move the capstan screws 3b, 3b, out from under the parts 25, 25, which actuate the piano hammers, so that they will not move. In this position, the wires d, 20d, set in the rear, or left hand, ends of the keys shove the rods 20c, 200, set in the arms 20, 20, backward, and as the frames 20, 20, move backward, the rollers 20c, We, set in the arms 20, 20, will shove the rear, or left hand, ends of the levers l9, I9, downwards, thus raising the wires I92), I9b, and so lifting the balls I10, I10, off their seats, thereby opening the main dashpot valves and so allowing the plungers l'la, Ila, to move up and down freely.

This inward or backward motion, to the left, viewing Fig. 1, also moves the end of the keys underneath the pushup pieces 1, 1, thus connecting the keys directly through the pushup pieces I, 1, levers 8, 8, pushup pieces 9, 9, and levers l0, I0, with the movable circuits l2, l2. Any movement of a key will now push the movable conductor I2, positively in between the stationary transferring plates l4, 14, in direct conformity with the movement of the key, and gravity and the returning spring 10c will keep the movable circuit l2, the lever 1, and the intermediate parts pressing down upon the key on its return movement, whether that movement be fast or slow, so that the movable circuit will move in, andout, exactly, in proportion to the movement of the key.

Whenever the key is depressed to the bottom, the plate, l2, will be pushed allthe way in between the plates l4, It. In this position, it gives the fullpowered sustained tone of the instrument, which continues at full power as long as the key is held down. It must be remembered that the same motion that pushes the keyboard inward or backward, also disconnects the piano action and the dashpots, or other return retarding devices.

As the key is depressed and the plate, [2, is moved in between the plates, l4, l4, the tone gradually swells, grows louder and louder. to a maximum, and so makes a crescendo. As the key is allowed to come up, or return to its normal position, the plate, I2, is withdrawn and the tone gradually dies away to nothing, and so makes a diminuendo. If the key is moved up and down slightly and rather rapidly, a vibrato is produced. This puts under the musicians finger, with the simplest and easiest of technique, every power, or practically every power, of the violin bow, and the other bowed instruments.

With the herein disclosed exceedingly easy powers of expression, it will be seen that a musician can, with little practice, play the parts of two or more bowed instruments with very great delicacy, beauty and finish.

These powers of expression disclosed by me herein, combined with the powers of tone building, invented by the said Dr. Thaddeus Cahill, also make it possible to produce all, or almost all, the effects of the bows, as well as of the brasses and Woodwinds, since their various tone colors can be produced to perfection. Moreover, it is also much easier to control the expression, by the fingers, through these herein disclosed delicate devices, than it is by the bow, or the lips, and the wind pressure created by the lungs, which require the co-acting of the diaphragm and many muscles in the abdomen, back, both sides, and between the ribs, as well as by the cheeks, and lips, and the resonance chambers in the throat, head and nose.

Many forms of mechanism for producing the desired results may be employed, the end sought being to vary the power of the electric current, with the utmost precision and delicacy, so as to produce the effects of all or, practically all known instruments. Whether these results are obtained by the mechanisms I have shown here, or in some other way, is immaterial, being all within the scope of my invention. The mechanisms illustrated are merely my preferred form to which, obviously, I am not limited.

Thus far, I have referred mainly to controlling the capacity circuit or the induced circuit. This is merely because I consider thatthe best, most perfect, most reliable, smoothest, simplest, and cheapest way of accomplishing the desired results. but there are other ways of producing approximately the same results, all within the scope of my invention. For instance, I may control the power of the primary or generator circuit directly, instead of controlling the power of the secondary or induced circuit. This may be done in various ways, but all within the scope of my invention. I have illustrated three such methods, in Figs. 6, 11, 11A, 11B and 13. Fig. 6 illustratesa method of closingthe circuit gradually through a number of current impeding devices, by dipping the ends of the wires to which they It is my preferred method of operation, 

